Police floodlights shine on the abandoned building on Main St. in Herkimer early this morning. (AP)

HERKIMER — Crazed upstate gunman Kurt Myers’ final victim was a rookie FBI tactical dog who was remembered fondly for making the “ultimate sacrifice” for his handlers.

Myers shot dead Ape, a 2-year-old Czech German Shepherd, this morning as police and federal agents stormed an abandoned building in downtown Herkimer where the wanted killer of four was hiding out.

Officers returned fire, and shot Myers dead.

No one was sure of a motive for Myers’ killing spree Wednesday, in which he shot dead two people and wounded two more at a barber shop in Mohawk, NY and then drove to next-door Herkimer, where he killed two more people at a car wash.

After the killings, Myers, 64, a loner who never seemed to talk to anyone, holed up all night in the an abandoned building in Herkimer that once housed a bar.

When police and federal agents finally moved in at 8 a.m., Myers was ready, armed with a rifle and a cache of ammo.

“He engaged in gunfire when he saw the team,” said State Trooper Jack Keller, a state police spokesman.

Myers shot at Ape through an open doorway. “We’re pretty sure it would have been an officer if it was not the dog,” said Keller. “Myers was in waiting.”

Officers removed Ape from the scene in a metal casket intended for small children.

“Our heart goes out to the handler of the canine, and the canine. We consider them part of law enforcement, and we do feel their loss,” said State Police Superintendent Joseph D’Amico.

“He just said that the guys were in the barbershop and this guy comes in and he says, ‘Hi John, do you remember me?’ and my brother said, ‘Yes, Kurt, how are you?’ and then he just started shooting,” Seymour’s sister Mary Hornett said.

Seymour was hospitalized in critical condition, but was improving after he was shot in the left hand and right hip.

“My brother couldn’t think of any reason why he would do such a thing,” Hornett said of Myers, a former customer who hadn’t been been to the shop in years.

Before Myers went off on his shooting rampage on Wednesday, he torched his apartment in the nearby village of Mohawk, officials said.

Renshaw was a 23-year state corrections employee at Mid-State Correctional Facility near Utica.

Authorities couldn’t immediately figure out what sparked the loner Myers to go off on his killing spree.

Gov. Cuomo called the attacks a “truly an inexplicable situation.”

The killer’s next-door neighbor, Traci Randall, recalled her only interaction with him, when Myers accused her son of shooting an air pellet at his Jeep.

“He would walk by himself. He was kind of a loner. No wife,” she said.

Another neighbor, Gary Urich, said he once said “hello” to Myers in passing.

“I said, ‘How are you doing?’ No response. He just walked by,” Urich said.

The closest Myers came to social interaction appeared to be his regular trips to Cangee’s Bar and Grille in Herkimer, employees said.

He never spoke to anyone and would leave after downing one or two bottles of Coors Light, according to workers.

Employees didn’t even know his name, until his mug shot was splashed across the local news yesterday.

Myers was “just an odd little man,” said Cangee’s owner Candy Rellin.

Herkimer is a village of 7,700 named for the German immigrant family that settled in the western Mohawk Valley in the 1720s. The economically distressed villages are 2 miles away from Ilion, where a 2-century-old Remington Arms gun plant is a major employer.

With Post Wire Services and additional reporting by David K. Li in New York